Toothbrush attachment



y 1963 M. MORET TOOTHBRUSH ATTACHMENT Filed April 1'7, 1961 INVENTOR T%Sw dn o a N M R O L E T T w? M Y M United States Patent 3,088,148TOOTHBRUSH ATTACHMENT Michel Moret, Chenes Bougeries, Geneva,Switzerland,

assignor to Etahlissement AESUP, Vaduz, Liechtenstein, a firm ofLiechtenstein Filed Apr. 17, 1961, Ser. No. 103,482 2 Claims. (Cl.15-22) This invention relates to a toothbrush attachment, andparticularly such an atachment for a motor unit having a rotationallyoscillatory shaft.

In U.S. Patent No. 2,917,758, an electrically-operated toothbrush isdescribed comprising a motor unit having a shaft on the end of which abrush head is mounted. The shaft is rotationally oscillated in use, andthe corresponding movement of the brush bristles efiects a brushing ofthe teeth in the longitudinal direction thereof.

in order to permit the electrically-operated toothbrush to be used bydifferent members of the family, and to permit replacement of Worn brushheads, it is desirable to arrange the brush portion for convenientattachment to the motor unit and removal therefrom. Further, forhygienic reasons it is desirable for the brush attachment to include allportions normally inserted in the mouth. This may be accomplished byproviding an attachment having a stem of sufficient length, with thebristles at one end and a coupling at the other end adapted forattachment to the shaft of the motor unit.

For greatest usefulness, the coupling should fulfill severalrequirements. It should permit convenient attachment and removal, and beadapted to rotationally oscillate the brnsh stern in a positive mannerwithout undue wear. It should also resist forces tending to detach thebrush from the motor unit when the bristles are presssed against theteeth during cleaning. Finally, it is advantageously designed so that itcan be formed by molding in plastic material, so that the attachmentunit can be economically manufactured without metal portions which wouldcontact the teeth during the cleaning operation and give rise todiscomfort or injury.

The present invention provides a toothbrush attachment which meets theforegoing requirements.

In the drawings:

FIG. 1 is an overall view of the motor unit with the toothbrushattachment in place;

FIG. 2 is an enlargement of a portion of FIG. 1, with the attachmentremoved from the motor unit shaft;

FIG. 3 is an end view of the toothbrush attachment, taken from thecoupling end;

FIG. 4 is a view at right angles to FIG. 2, with the attachment inposition on the motor unit and portions shown in cross-section; and

FIG. 5 is an end view of a modified coupling, with the cooperatingportion of the motor shaft shown in crosssection.

Referring to FIGS. 1-4, a motor unit is shown in the form of a handlehaving internal structure for imparting rotational oscillation to shaft11. The motor unit may be, for example, of the construction shown in theaforesaid US. patent.

The end portion 12 of shaft 11 is formed with a noncircularcross-section, and as here shown the cross-section is substantiallyrectangular. The narrow sides 13 may have a slight curvature. Atransversely-extending pin 14 is provided. Advantageously this islocated on one of the wide sides of the shaft end, and spaced asubstantial distance from the tip of the shaft. The shaft end may be ofplastic material and, for strength, may be molded or otherwise aflixedto a steel core 15, as shown in FIG. 4.

The toothbrush attachment comprises a stem 21 on 3,088,148 Patented May7., p 19 63 "ice one end of which are laterally-extending bristles 22.At the other end is a coupling, generally designated 23. Stem 21 may beof plastic material, such as nylon, with the bristles set in in knownmanner, and the coupling 23 formed by molding. It is desirable for themid-portion of stem 21 to be fairly slender so that the brush mayreadily be inserted in the mouth. However, to provide adequate strengthin coupling 23, that end of the stem is enlarged.

The coupling comprises a socket 24 of non-circular cross-section adaptedto mate with the motor unit shaft end 12. As here shown, socket 24 has asubstantially rectangular cross-section. =A longitudinally-extendingslot 25 is formed in the wall of the socket, with its open end 26 at theopen end of the socket. Opposed transversely-extending recesses 27, 27'are formed in the sides of the slot near the open end 26 thereof, toprovide a seat for pin 14 when in mating position.

The dimensions of the slot and recesses are predetermined to yieldablysecure the toothbrush attachment on the motor unit shaft when in matingposition. As shown, the Width of slot 25 is less than that of pin 14,and opening 26 is flared so that the pin can readily enter the slot andbe yieldably secured in recesses 27, 27. Due to the resiliency of thematerial of which the stem is made, the stem 21 can readily be pushedinto mating engagement with the motor unit shaft, and removed therefrom.By enlarging the coupling end, the walls are adequately thick to permitrepeated attachment and detachment without injury to the coupling, andto exert adequate force on pin 14 to retain the attachment in coupledposition.

The non-circular cross-section of the socket effectively transmitsrotational oscillation from shaft 11 to stem 21, Without requiring thesides of the slot to withstand rotational forces. Thus, the forces dueto rotational oscillation do not tend to spread the slot walls and allowthe attachment to slip off.

When the toothbrush is in use, the bristless 22 will be pressed againstthe teeth, and consequently there will be a lever action at the couplingend 23. In order to prevent this lever action from detaching the stem,it is ad vantageous to locate slot 25 in a longitudinal plane throughthe stern which is generally parallel to bristles 22, and preferably onthe same side of stem 21 as the bristles. Thus, in the specificembodiment shown slot 25 is on the same side of stem 21 as bristles 22,as best seen in FIG. 4.

To further resist lever action, it is advantageous to make thelongitudinal extent of slot 25 less than the longitudinal extent ofsocket 24, as shown. Thus, when the attachment is in mating position,the extreme end of the motor unit shaft will be encircled by the Wallsof the socket, and there will be less tendency to spread the slot walls.Further, by positioning the pin-engaging recesses 27, 27' near the openend 26 of the slot, the walls of the remainder of the slot may be madesufiiciently thick to provide a relatively strong socket, while at thesame time providing sufficient resiliency to permit the attachment to bepushed onto the shaft.

It will be seen that attachment of stem 21 to the motor unit is verysimple and convenient. With the parts oriented as shown in FIG. 2, thestem is axially pressed onto the shaft end 12. When slot opening 26reaches pin 14, the pin pushes aside the lips of the slot and seats inrecesses 27, 27'. To separate, the stem is pulled axially away from themotor unit. Despite the relative ease of axial attachment andseparation, the coupling effectively transmits rotational oscillationand resists the lever action resulting from. pressing the bristlesagainst the teeth in cleaning.

FIG. 5 shows a modification in which the coupling 23' is similar tocoupling 23 of the preceding figures, but includes a counter-slot 28opposite the main slot 25. Counterslot 28 provides somewhat greaterflexibility in the sides of slot 25 at theopen end thereof to facilitateattachment and removal. The depth of slot 28 is less than the wallthickness so that adequate wall strength still remains.

The toothbrush attachment of FIG. 5 may be employed with the motor shaftend configuration shown in FIGS. 2 and 4.

counter-slot 28 when in mating engagement. This further assures positiverotational oscillation of the toothbrush attachment without wear of thecoupling or tendeney to spread the walls of slot 25.

I claim: 7

1. A toothbrush attachment which comprises a stern havinglaterally-extending bristles at one end thereof and a coupling at theother end thereof, said coupling having a longitudinally-extending,socket of non-circular cross-section, a longitudinally-extending slot inthe wall of said socket and open toward said other end of the stem thewidth of the slot being less than the width of the socket in thecorresponding direction, opposed transversely-extending recesses in thesides of said slot near the open end thereof, and alongitudinally-extending counter-slot in the inner wall of said socketon the other side of the socket from said slot, the depth of thecounterslot being less than the wall thickness and the width of thecounter-slot being less than the width of the socket in thecorresponding direction.

2. A toothbrush attachment for a motor unit having a rotationallyoscillatory shaft end of rectangular crosssection with 'atransversely-extending pin in one of the If desired, however, the motorshaft end 12, may be provided with a pin or tongue 29 which fits in thewide sides thereof and spaced a substantial distance from the endthereof, which attachment comprises a stem of plastic material havinglaterally-extending bristles at one end thereof and a coupling at theother end thereof, said stem being enlarged at the coupling end thereof,a longitudinally-extending socket in said coupling end having arectangular cross-section adapted to mate with the motor unit shaft end,the longer cross-sectional dimension of said socket extending generallyperpendicular to said bristles, a longitudinally-extending slot in thewall of said socket on the same side of the stem as said bristles andopen at the open end of the socket, the width of the slot being lessthan the widthof the, socket in the corresponding direction, and opposedtransversely-extending recesses in the sides of said slot' near the openend thereof adapted to receive the transversely-extending pin on themotor unit shaft, said slot being dimensioned to yieldably secure thetoothbrush attachment on the motor unit shaft when in mating positiontherewith and the.

longitudinal dimension of said slot being less than the longitudinaldimension of said socket, and a longitudinallyeXtending counter-slot inthe inner wall of said socket on the other side of the socket from saidslot, the depth of the counter-slot being less than the wall thicknessand the width of the counter-slot being less than the width of thesocket in the corresponding direction.

References Cited in the file of this patent UNITED STATES PATENTS2,130,661 Zaelest Sept. 20, 1938 2,158,738 Baker et a1. May 16, 19392,206,726 Lasater July 2, 1940

1. A TOOTHBRUSH ATTACHMENT WHICH COMPRISES A STEM HAVINGLATERALLY-EXTENDING BRISTLES AT ONE END THEREOF AND A COUPLING AT THEOTHER END THEREOF, SAID COUPLING HAVING A LONGITUDINALLY-EXTENDINGSOCKET OF NON-CIRCULAR CROSS-SECTION, A LONGITUDINALLY-EXTENDING SLOT INTHE WALL OF SAID SOCKET AND OPEN TOWARD SAID OTHER END OF THE STEM THEWIDTH OF THE SLOT BEING LESS THAN THE WIDTH OF THE SOCKET IN THECORRESPONDING DIRECTION, OPPOSED TRANSVERSELY-EXTENDING RECESSES IN THESIDES OF SAID SLOT NEAR THE OPEN END THEREOF, AND ALONGITUDINALLY-EXTENDING COUNTER-SLOT IN THE INNER WALL OF SAID SOCKETON THE OTHER SIDE OF THE SOCKET FROM SAID SLOT, THE DEPTH OF THECOUNTERSLOT BEING LESS THAN THE WALL THICKNESS AND THE WIDTH OF THECOUNTER-SLOT BEING LESS THAN THE WIDTH OF THE SOCKET IN THECORRESPONDING DIRECTION.